docs: def load_tsv(filename, sep='\t', **kw):
      '''
      load_tsv(filename) yields a pandas dataframe of the contents of the TSV file. If pandas cannot
        be loaded, then an error is raised.
  
      All optional arguments are passed along to the pandas.read_csv function. Note that this function
      is identical to the load_csv() function except that it has a default sep value of '\t' instead
      of ','.
      '''
      import pandas
      if any(filename.endswith(s) for s in ('.gz', '.bz2', '.lzma')):
          with gzip.open(filename, 'rt') as fl: data = pandas.read_csv(fl, sep=sep, **kw)
      else:
          with open(filename, 'rt') as fl: data = pandas.read_csv(fl, sep=sep, **kw)
      return data